A 3-phase boost converter for lowering the input current distortion of a VSI drive using mutually coupled DC-link inductors

This paper presents a 3-phase rectifier topology that superimposes a high frequency switchmode power converter on top of a standard diode rectifier. The switchmode converter uses a 3-phase Y-connected bi-directional switch (3/spl phi/ Y-switch) network and a single switch boost converter to selectively draw a 180 Hz triangular wave current from the 60 Hz AC-line. Due to the mutual coupling of the rectifier DC-link inductors, this current flows back to the AC-side by splitting equally between the upper and lower rectifier DC rails. This current path, together with the current path associated with "standard diode rectifier" operation, produces a high quality sinusoidal line-current waveshape with very low line current harmonic distortion; ideally 4.7%.